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Automatic text classification is the problem of automatically assigning predefined categories to free text documents, thus allowing for less manual labors required by traditional classification methods. When we apply binary classification to multi-class classification for text classification, we usually use the one-against-the-rest method. In this method, if a document belongs to a particular category, the document is regarded as a positive example of that category; otherwise, the document is regarded as a negative example. Finally, each category has a positive data set and a negative data set. But, this one-against-the-rest method has a problem. That is, the documents of a negative data set are not labeled manually, while those of a positive set are labeled by human. Therefore, the negative data set probably includes a lot of noisy data. In this paper, we propose that the sliding window technique and the revised EM (Expectation Maximization) algorithm are applied to binary text classification for solving this problem. As a result, we can improve binary text classification through extracting potentially noisy documents from the negative data set using the sliding window technique and removing actually noisy documents using the revised EM algorithm. The results of our experiments showed that our method achieved better performance than the original one-against-the-rest method in all the data sets and all the classifiers used in the experiments. 相似文献
63.
Word sense disambiguation (WSD) is meant to assign the most appropriate sense to a polysemous word according to its context. We present a method for automatic WSD using only two resources: a raw text corpus and a machine-readable dictionary (MRD). The system learns the similarity matrix between word pairs from the unlabeled corpus, and it uses the vector representations of sense definitions from MRD, which are derived based on the similarity matrix. In order to disambiguate all occurrences of polysemous words in a sentence, the system separately constructs the acyclic weighted digraph (AWD) for every occurrence of polysemous words in a sentence. The AWD is structured based on consideration of the senses of context words which occur with a target word in a sentence. After building the AWD per each polysemous word, we can search the optimal path of the AWD using the Viterbi algorithm. We assign the most appropriate sense to the target word in sentences with the sense on the optimal path in the AWD. By experiments, our system shows 76.4% accuracy for the semantically ambiguous Korean words. 相似文献
64.
Young-Pyo Seo 《Inter-Asia Cultural Studies》2017,18(2):197-217
This paper discusses the legacy of Stuart Hall’s cultural studies approach to socialist politics. Like many other socialist thinkers, his ideas are the direct outcome of political intervention, often through the form of theoretical practice. Because gaps will always remain between reality and theoretical explanation, political intervention tends to be an overreaction to social change or the underestimation of people’s power. Hall’s political practice cannot therefore be exceptional in that it is far from perfect. This paper attempts to establish a balance sheet in terms of his involvement in the debate on the nature of British society, Thatcherism and neo-liberalism. From this examination, some key concepts will be employed to analyse the nature of Korean society in relation to neo-liberal restructuration and the neo-liberal historic bloc. Discussing Hall’s ideas and applying these to Korea, the paper sets out to demonstrate both weaknesses and strengths in Hall’s thought. The strength consists of his open-ended and empirically sensitive reformation of Marxism. On the other hand, the core weakness is found in his post-Marxist epistemological relativism. The main argument set out here is that, in order to develop and refine Hall’s thought, there should be an ontologically realist position compatible with epistemological relativism. For this difficult task, the concept of needs can be suggested as a fresh starting point. 相似文献
65.
Karrie A. Shogren Hyojeong Seo Michael L. Wehmeyer Susan B. Palmer James R. Thompson Carolyn Hughes Todd D. Little 《Psychology in the schools》2015,52(9):874-891
The Supports Intensity Scale–Children's Version (SIS‐C) was developed to assess the support needs of children and youth aged 5 to 16 years with intellectual and developmental disabilities. Data from the standardization sample of the SIS‐C were analyzed to evaluate the impact of the age cohorts (5–6, 7–8, 9–10, 11–12, 13–14, and 15–16 years) used to stratify the sample on the measurement model, as well as the latent means, standard deviations, and correlations. The findings confirmed measurement invariance across age cohorts, but suggested that at the latent level, younger children, generally, have more intensive support needs and that as students with intellectual disability age, their support needs decrease. In addition, the 15‐ to 16‐year‐old cohort displayed differences in terms of the strength of correlations between support need domains, with stronger correlations than the other age groups. Implications for future research and practice are described. 相似文献
66.
Online communities are valuable information sources where knowledge is accumulated by interactions between people. Search
services provided by online community sites such as forums are often, however, quite poor. To address this, we investigate
retrieval techniques that exploit the hierarchical thread structures in community sites. Since these structures are sometimes
not explicit or accurately annotated, we introduce structure discovery techniques that use a variety of features to model
relations between posts. We then make use of thread structures in retrieval experiments with two online forums and one email
archive. Our results show that using thread structures that have been accurately annotated can lead to significant improvements
in retrieval performance compared to strong baselines. 相似文献
67.
Kay Kyeongju Seo 《The American journal of distance education》2013,27(1):21-36
This study focused on the effects of peer moderation on meaningful interactions in online discussions. A meaningful interaction was defined as a message relating to a discussion topic, responding to a previous message, and adding substance to the discussion. A randomized-subject, posttest-only control group design was used to test the first hypothesis, that a peer-moderated online discussion forum would contain more posts responding to previous comments than a nonmoderated forum, and the second hypothesis, that a peer-moderated online discussion forum would contain more substantive responses enriching the conversation than a nonmoderated forum. Both hypotheses were supported. Results showed that students responded to messages more actively and engaged in more in-depth discussions when discussions were moderated by a peer. 相似文献
68.
ABSTRACTSound effects and music can be used to complement instructional narrations in recorded media presentations. College students (n = 143) participated in a study examining the effects of music and sound effects on learning outcomes when compared to voice-only narration. Four groups of participants listened to a recorded short story and answered questions about the story. The control group’s story was a voice-only narration. The three treatment groups’ story was enhanced with one of the following: sound effects, music, or a combination of sound effects and music. Means for each group were not significantly different, and the difference of means between and within each of the groups was also found not to be significant. The results indicated that the presence of sound effects and music in an audio-only presentation did not significantly increase or decrease learning. 相似文献
69.
This paper describes the use of Pareto-optimal solutions for the screw kick in rugby. We attempted to optimise the initial
conditions for a screw kick. The optimisation was carried out using an elitist non-dominated sorting genetic algorithm. Distance
achieved in flight is considered as an objective function, as well as the lateral deviation between the ball and the touchline,
or the flight time. Six initial conditions were defined as control parameters: the magnitude of the velocity vector, the flight
path angle, the azimuth angle, the spin rate, the pitch angle and the yaw angle. The results are summarised as follows: it
is impossible for both objective functions to be satisfied simultaneously, although the greatest distance achieved in flight
and the smallest value of the lateral deviation between the ball and the touchline, or the least flight time, is the ideal
situation. This kind of conflicting solution is called a ‘Pareto-optimal solution’. The optimal kick in Pareto-optimal solutions
made by the leg nearest the touchline produces a greater flight distance than the optimal kick in Pareto-optimal solutions
made using the leg furthest from the touchline. The initial pitch angle, which is the angle between the longitudinal axis
of the ball and the horizontal plane, should be comparable to or slightly greater than the initial flight path angle in order
to satisfy the Pareto-optimal solutions. 相似文献
70.
When the boundary layer of a sports ball undergoes the transition from laminar to turbulent flow, a drag crisis occurs whereby
the drag coefficient (C
d) rapidly decreases. However, the aerodynamic properties and boundary-layer dynamics of a soccer ball are not yet well understood.
In this study we showed that the critical Reynolds number (Re
crit) of soccer balls ranged from 2.2 × 105 to 3.0 × 105. Wind-tunnel testing, along with visualisation of the dynamics of the boundary layer and the trailing vortex of a ball in
flight, demonstrated that both non-spinning and spinning (curved) balls had lowC
d values in the super-critical region. In addition, theRe
crit values of the soccer balls were lower than those of smooth spheres, ranging from ∼ 3.5 × 105 to 4.0 × 105, due to the effects of their panels. This indicated that the aerodynamic properties of a soccer ball were intermediate between
those of a smooth ball and a golf ball. In a flow visualisation experiment, the separation point retreated and theC
d decreased in a super-critical regime compared with those in a sub-critical regime, suggesting a phenomenon similar to that
observed in other sports balls. With some non-spinning and spinning soccer balls, the wake varied over time. In general, the
high-frequency component of an eddy dissipated, while the low-frequency component increased as the downstream vortex increased.
The causes of the large-scale fluctuations in the vortex observed in the present study were unclear; however, it is possible
that a ‘knuckle-ball effect’ of the non-rotating ball played a role in this phenomenon. 相似文献